The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art.
Implantation of in vitro grown bone has been proposed as a method of healing broken, diseased, or malformed bones in patients. In vitro bone grown typically requires a porous scaffold to support the growing bone material. While the porous scaffolds should approximate the mechanical properties of bone as closely as possible, traditional porous scaffolds, particularly polymeric porous scaffolds, exhibit considerably lower tensile strength, compressive strength, and modulus than natural, cortical bone.
Improvements to the mechanical properties of polymeric porous scaffolds have been made via the incorporation of an inorganic substance, or phase, either as a mixture of the polymer and inorganic substance, or where the polymer has been bonded to the inorganic substance as a composite material. In such composites, stress is transferred from the polymer to the inorganic substance which has a higher strength than the polymer. One such inorganic substance is Bioglass®, however this material has presented numerous challenges. For example, hydrophilic Bioglass® particles are not compatible with hydrophobic polymers such as (poly)lactic acid. In the absence of a favorable interaction between the materials, they tend to phase separate, thereby compromising the integrity of composites formed of those materials. Where linkages between PLA and Bioglass® have been made, it is via a urethane chemistry and is not well-suited to medical applications due to concerns about the toxicity of the isocyanate chemistry used.
The polymer composites described herein provide for strong bonds between polymers and inorganic materials, thereby increasing the strength of the corresponding composites.